FC 4, test cycles, etc.

[Leaf]

I am about to change my machines and will need to install an OS from scratch.  
I am interested in jumping into FC 4 but I would like to know how upgrading 
through the test cycles is handled and once FC 4 becomes finalized if I would 
be able to just move into the official realease without much problems OR if 
fresh installs between phases is the acceptable, headache-free norm?